New findings from scientists at Royal Holloway, University of London in the UK reveal that pregnant women exhibit increased activity in the right side of the brain - an area related to emotional skills.
The research will be presented by Dr. Victoria Bourne, from the Department of Psychology at Royal Holloway, today at the British Psychological Society's annual conference.
"Our findings give us a significant insight into the 'baby brain' phenomenon that makes a woman more sensitive during the child bearing process," says Dr. Bourne.
Previous studies have suggested that slight decreases in learning and memory during pregnancy help to prepare the mother for cognitive benefits once the baby is born.
In 2008, the American Psychological Association reported that the brain shrinks slightly during pregnancy. The association cited a study from the American Journal of Neuroradiology, which found that the brain volume of women shrinks by 4% during pregnancy and then returns to normal after delivery.
In this latest study, Dr. Bourne and colleagues observed that, compared with new mothers, pregnant women use the right side of their brain more when they look at faces with expressions that are emotive.
'Pregnant women use right brain more than new mothers'
"The results suggest that during pregnancy, there are changes in how the brain processes facial emotions that ensure that mothers are neurologically prepared to bond with their babies at birth," Dr. Bourne says.
The new findings reveal pregnant women use the right side of their brain more than new mothers do.
To conduct their study, the investigators assessed the neuropsychological activity of 39 pregnant women and new mothers while they observed images of adult or baby faces with positive or negative expressions.
They used a test known as the chimeric faces test. This involves images comprised of half of a neutral face and half of an emotive face, which the researchers say allows them to observe which side of the subjects' brains is being used to process either positive or negative emotions.
The team found that pregnant women employed the right side of their brains more than new mothers did, and this was particularly the case when they were processing positive expressions.
Commenting on their findings, Dr. Bourne says:
"We know from previous research that pregnant women and new mothers are more sensitive to emotional expressions, particularly when looking at babies' faces. We also know that new mothers who demonstrate symptoms of postnatal depression sometimes interpret their baby's emotional expressions as more negative than they really are."
Speaking with Medical News Today, she explained that this effect may be preparatory:
"So, in the final stages of pregnancy, the brain is becoming more strongly lateralized so that any increased sensitivity to facial emotion is established by the time the baby is born."
She explained that this might help with early monitoring of the baby's emotional state; however, she added that they did not have a control group of women without a child in this study, so they are currently working on getting a control group to look at other possibilities.
She adds that unravelling the processes behind such changes "is a key step towards understanding how they might influence a mother's bonding with her baby."
Medical News Today recently reported on findings that suggested yoga could reduce the risk of pregnant women developing anxiety and depression. Researchers from that study calculated that a single session of yoga reduced self-reported anxiety by a third and stress hormone levels by 14%.